This invention relates to a method of handling and disposal of solids-laden bottoms produced in the processing of oil derived from retorting solid carbonaceous materials in a retort using heated solids to provide heat for the retort.
Gases and oil vapors are produced by retorting crushed oil shale, coal or tar sands. As used herein, the term retorting refers to the use of hot heat carrying solids to thermally convert the organic substances in these normally solid carbonaceous materials to a vapor product. The term retorting does not include liquefaction processes using heated liquids or slurries, or processes using direct combustion of the feedstock or heated gases to directly retort the feedstock. Retorting, therefore, produces a retort effluent containing oil vapors, gases, and spent solids. In retorting processes using solid heat carriers, the retort hydrocarbonaceous effluent product vapors contain an appreciable amount of particulate matter derived from the action of mixing the carbonaceous feed with the heat carriers. Moreover, the retort vapors contain impurities deleterious to use of the retort oils, for example, refer to U.S. Pat. No. 4,069,140. In a retort facility, the oils from the retort are processed in a number of ways which eventually produce a plus 950.degree. F. (510.degree. C.) bottoms or residual carbonaceous fraction which is laden with particulate matter derived from the carbonaceous feed. For example, the retort oils may be prerefined to fuel oil or a synthetic crude oil, or the retort oils may be treated to make the oil more pumpable in a pipeline, or the retort oils may be subjected to thermal cracking to produce chemical feedstocks.
Typically, the bottoms fraction containing appreciable matrix solids from the carbonaceous feed is subjected to steam stripping and the solids-laden residue delivered to a coking facility (e.g., a delayed or fluid bed coker) to remove as much of the useful product as is practical. The remaining solids are disposed of with other waste solids.